To provide a cleaning method which can easily remove foreign matter deposited on the surfaces of a heating member (heat drum) and an energizing member (counter roller) and to provide a cleaning method which never causes the deterioration of an elastic body when the surface of the member is made of the elastic body and can easily maintain and clean it.

The heat developing device processes a photothermographic element clamped and carried at a specific processing speed by the heating member for supplying heat to the photothermographic element and the energizing member energizing the element against the heating member and this cleaning method uses a water base mixed solvent as a cleaning agent for cleaning the heating member or energizing member of the heat developing device.